1. Field of the Invention
This invention relates to bulk material containers made from paperboard and the like.
2. Description of the Prior Art
A number of prior art bulk containers, such as disclosed in our U.S. Pat. No. 3,979,045, employ top covers or caps which fit over the top portion of the container; such top caps are sometimes difficult to position on a container due to the bulge of the unit from bulk material when full, and further such top caps tend to burst or work loose. Thus with such prior art containers, it is often required to utilize steel straps or tape to hold the top cap securely in place.
The prior art, as exemplified in U.S. Pat. Nos. 2,369,387, 2,559,320, 2,580,586, 3,326,447, 3,512,699, and 3,958,747, also contains a number of containers with covers having locking features for locking the covers on the containers. However, some of such covers cannot be used on bulk material containers due to the forces on the containers from bulk material, and further such covers cannot be readily removed without damage so that the container can be reused after removal of the contents.